[PATCH v1] arch: Add explicit linker script for u-boot-elf

[Michal Simek]

Hi,

On 26. 03. 20 15:39, Daniel Schwierzeck wrote:
> Hi Michal,
> 
> Am 26.03.20 um 14:54 schrieb Michal Simek:
>> Commit f4dc714aaa2d ("arm64: Turn u-boot.bin back into an ELF file after
>> relocate-rela")
>> introduce REMAKE_ELF option to recreate u-boot.elf from u-boot ->
>> u-boot.bin + DT -> u-boot.elf.
>>
>> The best is to ilustrate it from make V=1 output
>>   cat u-boot-nodtb.bin dts/dt.dtb > u-boot-dtb.bin
>>   cp u-boot-dtb.bin u-boot.bin
>> aarch64-linux-gnu-objcopy -I binary -B aarch64 -O elf64-littleaarch64  u-boot.bin u-boot-elf.o
>>   aarch64-linux-gnu-ld.bfd u-boot-elf.o -o u-boot.elf --defsym="_start"=0x8000000 -Ttext=0x8000000
>>
>> Last command has no explicit linker script passed that's why toolchain
>> internal linker script is used.
>> In Binutils 2.32 case it contains SIZEOF_HEADERS symbol which has changed
>> behavior by commit
>> https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=64029e93683a266c38d19789e780f3748bd6a188
>> which result in situation that program headers has changed from
>> (xilinx_zynqmp_mini_defconfig)
>>
>> Program Headers:
>>   Type           Offset             VirtAddr           PhysAddr
>>                  FileSiz            MemSiz              Flags  Align
>>   LOAD           0x0000000000010000 0x00000000fffc0000 0x00000000fffc0000
>>                  0x0000000000018918 0x0000000000018918  RW     0x10000
>>
>> to
>>
>> Program Headers:
>>   Type           Offset             VirtAddr           PhysAddr
>>                  FileSiz            MemSiz              Flags  Align
>>   LOAD           0x0000000000000000 0x00000000fffb0000 0x00000000fffb0000
>>                  0x0000000000028918 0x0000000000028918  RW     0x10000
>>
>> Xilinx tools like XSDB or Bootgen are using program headers for loading ELF
>> to the right location and by above binutils change ELF is loaded to
>> incorrect location.
>>
>> The patch is explicitly use u-boot-elf.lds (just cat now) for u-boot.elf
>> recreation which is called when REMAKE_ELF is setup.
>> By purpose u-boot-elf.lds doesn't contain OUTPUT_FORMAT/OUTPUT_ARCH to be
>> able to use by all archs.
>>
>> Signed-off-by: Michal Simek <michal.simek at xilinx.com>
>> ---
>>
>> Changes in v1:
>> - Compare to RFC
>> - MIPS has different elf entry point that's why I replaced simple cat with
>>   sed to setup proper entry point
>>
>> Sadanand, Mahesh: Please correct my description if I am wrong based on our
>> internal discussion about this issue.
>>
>> Tom: I have been told that it is GCC issue but I found that commit in
>> binutils.
>> I am not doing these makefile stuff that's why I expect this should be
>> changed a little bit. Also arch/u-boot-elf.lds is likely incorrect location
>> but didn't find any better.
> 
> maybe include/asm-generic/ ?

I will wait also for others to comment.

> 
>>
>> ---
>>  Makefile            | 11 +++++++++--
>>  arch/u-boot-elf.lds |  9 +++++++++
>>  2 files changed, 18 insertions(+), 2 deletions(-)
>>  create mode 100644 arch/u-boot-elf.lds
>>
>> diff --git a/Makefile b/Makefile
>> index be1513227361..7aebfc3a2de1 100644
>> --- a/Makefile
>> +++ b/Makefile
>> @@ -1654,12 +1654,19 @@ ifndef PLATFORM_ELFENTRY
>>  endif
>>  quiet_cmd_u-boot-elf ?= LD      $@
>>  	cmd_u-boot-elf ?= $(LD) u-boot-elf.o -o $@ \
>> -	--defsym=$(PLATFORM_ELFENTRY)=$(CONFIG_SYS_TEXT_BASE) \
>> +	-T u-boot-elf.lds --defsym=$(PLATFORM_ELFENTRY)=$(CONFIG_SYS_TEXT_BASE) \
>>  	-Ttext=$(CONFIG_SYS_TEXT_BASE)
>> -u-boot.elf: u-boot.bin
>> +u-boot.elf: u-boot.bin u-boot-elf.lds
>>  	$(Q)$(OBJCOPY) -I binary $(PLATFORM_ELFFLAGS) $< u-boot-elf.o
>>  	$(call if_changed,u-boot-elf)
>>  
>> +quiet_sed_elfentry = SED_ELF $@
>> +cmd_sed_elfentry =                                                      \
>> +	sed "s at PLATFORM_ELFENTRY@$(PLATFORM_ELFENTRY)@g" $< > $@
>> +
>> +u-boot-elf.lds: arch/u-boot-elf.lds prepare FORCE
>> +	$(call if_changed,sed_elfentry)
> 
> you could also run the script through the preprocessor like it's done
> for the other .lds files. This way you could use Kconfig options for
> stuff like PLATFORM_ELFENTRY.

Thanks for suggestion. I have tried it and also works and looks better.
Will wait for location and then will send v2.

M